Improvement in steam-engines



NITE STATES PATENT EETCE.,

GEORGE I. VVASHBURN, OF WORCESTER, MASSACHUSETTS.

IMPROVEMENT IN STEAM-ENGINES.

To all whom it may concern:

Be it known that I, GEORGE IoHABoD WASHBURN, of the city and county of Worcester, and State ot' Massachusetts, have made new and useful Improvements in vSteam-Engines 5 and Ido hereby declare the following to be a full, clear, and exact description of the nature, construction, and operation of the same, suflicient to enable one skilled in the art to which my invention is allied to construct and use the same, reference being had to the accompanying drawings, which are made part of this specieation, and in which similar letters refer to corresponding part-s in the different figures.

Figure 1 is au elevation of the steam-engine with slides, shaft, cranks, and y-wheels attached. Fig. 2 is a horizontal section onthe line m m, Fig. 3. Fig. 3 is avertieal section on the line y y, Fig. 2. Fig. 4 is an elevation of au engine similar in general character to theY engine represented in the other igures, but varying to some extent in the arrangement of the steam-passages.

This invention consists ot' a double engine having two or more pistons attached to a common crank-shaft, each piston workin g in a separate cylinder, and each cylinder havingits own valve and valve-chest outside the cylinder. The valve which governs the action of the steam upon `a given piston is moved precisely with and by direct attachment to the other piston. This motion is of the same extent as that of the piston which actuates it,

the two passing through'the corresponding portions ot' their strokes at the same time and rate.

The cranks to which the pistons are attached are set atan angle with each other of ninety degrees, and consequently one of them is one-half stroke or one-quarter of a revolution ahead of the other when the shaft is running in a given direction. Owing to the connection between the pistons and the cranks, each valve is passing ports while the piston to which itis attached is about the middle of its motion and at the point of greatest speed, while the piston which is governed by the valve is moving at its slowest speed, being at the end oi' its stroke.

In the drawings, A A represent the two cylinders, and B B the respective pistons. At-

tached to the cylinders are valve-chambers C C, occupied by valvesD D', which are respectively formed ot' two disks on a rod, E E. The upper end of the rod E is attached by crosshead F to the piston-rod G', and the upper end ofthe valverod E is attached by crosshead F to the upper end of the piston-rod Gr.

It will thus be perceived that each valve is attached to one piston, and is the means ot' actuating the other by the opening and closing of the steam-passages leading thereto and therefrom.

Each valve-chamber is an appendage to a given cylinder, and the -valve therein is made the means of opening and closing the steampassage of said cylinder and thus actuating the piston therein; but the motions of the valve are derived from the piston ot' another cylinder, and the required relation is preserved in this form of my engine bymeans of their common connection to a shaft, by means ot' cranks H H set at an angle ofninety degrees with each other.

In the form of engine illustrated in the drawings the pistons are double-acting; but it is possible to make each piston, in a sense, single-acting by placing two upon the saine rod, so that the steam acts upon them alternately.

The steam is admitted to the valve-chambers by means of the feed-pipe K, and exhausted through exhaust-pipe L.

It is necessary, either by means ot' the constructions of the valves or by the construction ofthe ports or channels which lead the steam from a given valve-chest to its cylinder, to cause them to work the steam, that if one valve, when at the top of its stroke, gives the steam to the upper side of its piston, the other valve, when atthe top of its stroke, shall give steam to the under side of its piston. The same is true of exhausting the steam. This may be done either by the construction of the valves, as shown in Fig. 1, in which the midy dle space is an exhaust-space in one valve and a steam-spacev in the other 5 or, as in Fig. 4, by causing the steam-passage from the upper side of one ot' the valves to lead to the under side of the piston, as by pipe M, while the corresponding passage N in the other valve leads to the upper side of its piston. The reversal of the action may be obtained in either way. l do not limit myself to any particular mode of obtaining it.

In consequence ot the action or ope-ration ot the crank-shaft and the method of moving the valves above explained, when the valve passes the ports and reverses the steam-pressure in a given cylinder the maximum rate of vertical motion of one crank is given to the valve, While the minimum vertical motion of the other crank is given to the piston upon which steam is reversed by said valve. The effect of this is a great reduction of the back-pressure of the steam in the cylinder and an increased eiiiciency of the steam on the receiving side of the piston. This is due to the fact that the valve has reversed the steam-pressure upon its pistou, fully opening all the ports before the piston has moved to any considerable extent, the 'ull pressure being thrown a-t once upon the receiving side of the piston and the exhaust side being fully opened to the passage of steam therefrom. v

The foregoing description refers to a double engine used With cranks connected upon a single shaft; but when used in connection with a hammer or pumping-piston and Without the cranks the pistons will move in a given direction until they meet some opposing object-as, for instance, the anvil, or the end ofthe steam or pump cylinder, or an elastic device or material provided for that purpose; but when used with the double crank the motions are modified in the manner so Well knownand understood as not to require special description. In either casewhether used with the crank or without it-the valve which regulates the How of steam to and from a given cylinder is actuated by the piston of the other cylinder, the use or disuse of the crank being determined by its purpose and application.

For a steam-hammer the hammer-face may be connected directly to the piston-rod, While for a steam-pump for air or Water a duplicate ings can be used as exhaust-valves and two more valves be placed iipon each cylinder zto control the inlet of steam thereto, accordi-ng to the position ot' the governor.

Having described myinvention, what I claim as new, and desire to secure by Letters Patent, isv The arrangement of the pistons B B and valves D D', the latter being respectively actuated by one piston, and the means ot' actuating the other piston, substantially as described.

GEO. I. WASHBURN,

Witnesses; 4

S. P. MORSE, WM. F. BARNEY. 

